Conventional containers for storing beverages, powder and other contents therein are provided with stoppers. Such stoppers are required to provide a variety of functions according to the uses or stored contents of storage containers.
For example, in case of a carbonated beverage container, the pressure in the container should be maintained at pressure higher than atmospheric pressure. Thus, it is important to keep hermetical sealing of a stopper during distribution of the container. In case of a large-capacity container, it is preferred that after the container has been opened, a stopper close and seal the container again to store remaining contents therein.
Further, in case of alcoholic liquors or medicines, it is preferred that after first opening of a stopper, the opening thereof can be checked.
As described above, conventional stoppers are manufactured variously and then used according to stored contents and functions of containers.